The invention relates generally to systems and methods that include powered units (power units—PUs, and most often hydraulic power units—HPUs) designed for operating “prime movers”. These systems utilize devices that move by receiving hydraulic and/or electric power and are primarily associated with pipelines. Although the prime movers described herein in detail have been designed specifically for downhole petrochemical well applications, the assemblies and associated valve operation and engagement with actuated hydraulic cylinders and pistons pose opportunities for optimizing the actuation and efficiencies in other applications. These applications include other technology fields involving; energy generation, distribution, and storage, including cogeneration, hydraulic power systems, air and water reclamation systems, as well as transportation systems including civilian and military automobiles, aircraft, and ships. The valve operations for the “prime movers”, include the use of selective bi-directional hydraulic/electric power unit (HPU's) where the hydraulic fluids can be air, gas, or liquid.